Method of treating knitted superpoly-amide textile fabric with an aqueous phenol bath subjected to ultra-sonic waves and fabric produced thereby



Aprll 2, 1963 H oos METHOD OF TREATING KNITTED SUPERPOLYAMIDE TEXTILEFABRIC WITH AN AQUEOUS PHENOL BATH SUBJECTED TO ULTRA-SONIC WAVES ANDFABRIC PRODUCED THEREBY Filed 001'. 1.6, 1958 United States Patent3,084,020 METHOD OF TREATING KNITTED SUPERPOLY- AMIDE TEXTILE FABRICWlTH AN AQUEOUS PHENOL BATH SUBJECTED T0 ULTRA-SQNIC WAVES AND FABRICPRODUCED THEREBY Hermann Loosli, Zurich, Switzerland, assignor, by mesneassignments, to Rene Ruegg, Zurich, Switzerland Filed Get. 15, 1958,der. No. 768,527 Claims priority, application dwitzerland May 30, 1956 9Claims. (Cl. 8-1301) This application is a continuation-in-part of mycopending application Serial No. 662,096, filed May 28, 1957, nowabandoned.

My invention relates to a method of improving synthetic fibers oforganic compounds, for instance synthetic fibers of straight molecularchain substances such as viscose fibers, acetate rayon fibers, nylon orcondensation products of terephthalic acid with glycol (Terylene), andpolyvinyl chloride products. Such substances, in form of fibrous stapleas well as in yarn form, are generally less elastic and not so soft asnatural vegetable or animal fibers. Besides, synthetic fibers have atbest an only slightly developed surface texture. Their smooth surface isdisadvantageous particularly in the manufacture of textile materialbecause of the absence of the desired fiber-friction resistance orgripping ability peculiar to other fibers such as cotton, fiax or sheepswool. It is also known that the threads in textiles produced from fibersof smooth surface may tend to become displaced within the web structure,thus impairing its utility.

Attempts have therefore been made to artificially impart to such fibroussubstances the desired adhesion or gripping ability together with thenecessary fiaccidity and softness. For instance, it has been proposed totreat the synthetic spun fibers with chemicals such as saponificationproducts or oxidation products obtained from parafl'in hydrocarbons; orby treating such fibers with a liquid dispersion of aerosol particlescontaining a wetting agent, in which the aerosol is obtained by thermaldecomposition of volatile compounds in gaseous condition. Another knownmethod involves producing bubbles and hollow spaces in the interior ofthe viscose bodies for increasing their heat-insulating ability andvolume While giving them a softer and fuller feel, a curled and scarredsurface, a reduced sheen and better permeability for dyes. Such hollowspaces are produced by decomposing concentrated hydrogen peroxide bymeans of catalysers within the interior of the viscose bodies.Esterification of cellulose and cellulose hydrate material, such asrayon and cellulose Wool, by applying a fatty acid hydride at elevatedtemperature and simultaneously applying alkali salts of weak acids toact as catalysers, also have the effect of somewhat modifying theproperties of the original fibers in the desired sense. Such esterifiedproducts, however, are not resistant to soap and caustic soda because ofpronounced swelling, so that subsequent processing is necessary forminimizing this disadvantage.

Brief mention may be made of a known mechanical method attempting toartificially roughen and curl the synthetic fibers, for instance bypassing them between a pair of rippled rollers.

The prior art methods for roughening and curling the fibers have beenfound to have the considerable disadvantage that the fibers so processedmay in some cases become weakened, and that components of the chemicalreagents may deposit themselves within the fibers or in the spun threadswith the effect of impairing their properties, for instance the desiredporosity. The mechanical curling methods produce fibers which are wavyin only one plane, which is wholly insufficient for most purposes.

It has also been proposed to treat spun thread by 3,034,020 PatentedApr. 2, 1953 ultrasonics either by imparting ultrasonic oscillations tothe spinning liquid or into the precipitation bath or into the bath ofcleaning water subsequently used in the spinning of synthetic material.Such treatment also results in a loosening of the spun material.However, this method has not been used in actual practice because theultrasonic elfect must be maintained for too long a period of time untila visible loosening of the yarn texture can be observed, thus making themethod uneconomical.

It is an object of my invention to provide a novel method which improvessynthetic fibers of all kinds, or spun threads, yarn or fabrics madefrom suchmaterial, but which avoids the above-mentioned deficiencies ofthe methods heretofore available for such purposes.

According to my invention, the synthetic fibers or the spun products orfabrics made therefrom are processed within a bath which containschemical additions for loosening and curling the texture of individualfibers and which is also subjected to ultrasonic oscillations. This hasthe effect that the ultrasonic oscillations augment and accelerate thechemical curling action of the additions upon the fibers so that theloosening in fiber texture is completed within much shorter time thanwhen ultrasonics alone or only the chemical additions alone areemployed. The ultrasonic oscillations may have a frequency of 20,000 to40,000 cycles per second, although oscillations of higher frequencies,such as up to about 60,000 cycles persecond, are likewise applicable.

The ultrasonic oscillations may be applied continuously. However,according to another feature of the invention, it is preferable to applythe ultrasonic oscillations intermittently, particularly in form ofindividual pulses or pulse trains. With such an intermittent operation,the

oscillation generating and issuing ultrasonic oscillator can be loadedby impulse generating power to a much larger extent than is possiblewith a continuous application of the oscillations. Damped or undampedoscillation pulses or pulse trains can thus be applied. The ultrasonicoscillations are generated, in the manner known as such, for instance byexcitation of a magnetostrictive body such as a nickel-iron rod, or bydischarge of electric capacitors.

Particularly when employing damped impulses prO- duced by discharge ofcapacitors with the aid of a commutator or the like, a simple andreliable impulse generator of low cost can be provided.

The process according to the invention will be further explained withreference to the examples described Presently EXAMPLE 1 Ladies Hose 0Superpolyamides The leg portion of the hose is produced from a yarn of30 den/10 (times) with a twist of 320 per meter. The edge and thereinforcement consist of a yarn 40 den/13 with a twist likewise of 320per meter. The weight of a single hose is approximately 10 g. Anumber-of hose, for

'to 6%, of one of the crystallized phenols such as monohydroxybenzeneand has a temperature of about40 C. The second aqueous bath contains asolution of 3 g./l. caustic soda and has a temperature of 65 C. Thethird bath contains a solution of 1 g./l. of a penetration agent, forexample triethanolamine and has a temperature of 65 C. The hose aresuccessively drawn or conveyed from one bath to the other, theprocessing treatment in the first bath being no longer than fifteenseconds. The duration of the subsequent processing in the other baths isless critical and hence may be permitted to be less uniform. Suchfurther processing is preferably of longer duration than in the firstbath, for example twenty to thirty seconds in each subsequent bath.

EXAMPLE 2 Material: Charmeuse (tricot cloth) of superpolyamide nylon 40den., 70 g. per m. The material to be processed is passed on an endlessbelt through three different baths. The first bath is the processingbath for opening i.e. curling the fibers. The second bath is theneutralizing bath. The third bath serves as a rinsing bath. The firstbath is an aqueous solution of phenol as the roughening and curlingagent, namely 40 g. per 1 liter of water, i.e., in the order of about47, and has a temperature of 45 C. The second bath is an aqueoussolution containing 3 grams caustic soda per liter of water, thesolution having a temperature of 65 C. The third bath is an aqueoussolution containing 1 gram of penetrating agent, namely triethanolamine,at a temperature of 65 C.

Duration of processing:

In the first bath about fifteen seconds, In the second bath about thirtyseconds, In the third bath about thirty seconds.

EXAMPLE 3 A web of nylon (superpolyamide) made of 30 den./ 600 T/lfibers, is conveyed through three baths by means of an endless belt asin Example 2 above. The composition, concentration and temperature ofthe respective baths are the same in Example 2. The web is subsequentlydried under slight tension. The processing treatment in the respectivebaths is the same as in Example 2.

An apparatus for performing the above-described method, is schematicallyillustrated on the drawing which, for simplicity, shows only one bathinstead of the two or three preferably used in accordance with theabove-described examples.

The processing tank 7 shown on the drawing may consist of wood, forexample. It may have a length of 1.5 m., a width of 60 cm. and a heightof 60 cm. The tank is partly filled with the above-mentioned respectiveprocessing liquid. For the first bath, for example, it is filled with anaqueous solution of phenol as the curling agent. The temperature of thefirst bath is approximately 45 C. The web 11 to be processed (Example 2)is carried in a net from the supply roller 1 through guide rollers 2, 3,4, 5 into the second bath and then into the third bath where theprocessed web is washed. Mounted in a wall of tank 7 is an ultrasonicoscillator 8 in such a position that it radiates its ultrasonic poweroutput into the interior of the tank 7. The ultrasonic oscillator mayconsist of a magnetos-trictive device having a nickel-iron rod excitedby a magnetic field coil to oscillate at a frequency of approximately38,000 cycles per second and to provide a radiating output powercapacity of about 120 watts. Instead of a magnetostriotive oscillator, apiezoelectric oscillator may also be used.

The oscillator 8 is excited by the discharging current of a capacitor 10whose charging and discharging is controlled by a switching device 9.The switching device 9 is shown to have an oscillator contact whichmaybe operated mechanically or electromagnetically and makes alternatecontact with stationary contact pieces and 16 respectively. When contact12 engages contact 15, the capacitor -10 is charged from adirect-current source 13 through a calibrating resistor 14. When contact12 engages contact 16, the capacitor 10 discharges through the magnetcoil of the oscillator 8 and excites the oscillator in accordance withthe natural frequency of the oscillatory circuit formed by the capacitor10 and the oscillator. The oscillations then decay in accordance withthe damping of the oscillatory circuit. The voltage at the capacitor 10,in the processing example here considered, is approximately 1,000 voltsand the peak current intensity of the discharging current isapproximately 200 amps. It will be understood that the oscillations mayalso be excited by other devices such as electronic tube circuitsoperating, for instance, with thyratrons instead of the mechanicalswitch 12.

Depending upon the intensity of the ultrasonic pressure field within thebath through which the web material 11 is being passed, the necessaryduration of the treatment may vary. For instance, in the above-describedExample 2, the processing period with a sonic power of watts, a bathtemperature of 45 C. and the above-specified chemical additions, isapproximately fifteen seconds. With a smaller ultrasonic power and otherbath composition and temperatures, the processing period may amount upto about one minute. Bath temperature, ultrasonic power output and thechemical bath composition can be so chosen relative to each other thatthe processing period is best adapted to the kind of web material, itstraveling speed and other operating conditions.

Depending upon the particular operating conditions and the properties ofthe material to be processed, the method can be modified in variousways. For instance, the frequency of the ultrasonic oscillations can beincreased or reduced; that is, the most favorable frequency can bedetermined by sample testing for each particular type of syntheticfiber. Tests have shown that these frequencies, in general, are within20,000 to 60,000 cycles per second.

The duration of the individual impulses in the abovedescribed examplewas approximately six cycle periods, that is about 0.00016 second, andthe interval of interruption between consecutive pulse trains wasapproximately 0.5 second. In accordance with the example just given, itis preferable to operate the device 9 so that the individual ultrasonicpulse trains are spaced from each other an interval of time much longerthan the duration of an individual pulse train. In this manner, theultrasonic oscillator 8 may be given a very great instantaneous poweroutput during the intervals of pulse duration, while the over-all powersupply for rated power of the equipment is kept within reasonablelimits.

Due to the damping in the discharging circuit, which, if necessary, maybe increased by inserting series resistance between the capacitor 10 andthe oscillator 8, any desired damping of the impulse trains can beobtained, for instance so that the decay .to negligible amplitudes takesplace within an interval of several cycles.

The ultrasonic oscillator 8 may also consist of mutually spacedcapacitors electrodes which pass an electric discharge directly throughthe liquid.

The method according to the invention can be applicable simultaneouslyto any desired number of webs, threads or individual filaments ofsynthetic material. In such cases, a single bath, in a tank or vessel ofproper size, can be used for a multiplicity of webs or threads orfilaments, for instance 20 or more, without necessarily increasing thepower output of the ultrasonic oscillator.

As a result of the described process, the web or other fibrous materialexhibits increased elasticity and becomes generally more similar tonatural fibers or webs made of natural fibers.

I claim:

1. The method of treating a knitted textile fabric comprised ofsuperpolyamide multi-filament yarn of which the individual filaments arecontinuous, which comprises subjecting said fabric to an aqueous bathcontaining a solution of the order of four to six percent, based on theweight of the solution, of a chemical fiber-curling agent forsuperpolyamides, said agent consisting essentially of a crystallizedphenol, and simultaneously imparting pulse trains of ultrasonic acousticwave oscillations to the bath, the frequencies of said oscillationsbeing within the range of 20,000 to 60,000 cycles per second, theduration of such treatment in said aqueous bath being not longer than 15seconds, whereby respective individual ones of said continuous filamentsbecome curled and spread apart at portions thereof between crossingpoints of the knitted filaments, the effect over the fabric beinguniform.

2. The method of treating a knitted textile fabric comprised ofsuperpolyamide multi filament yarn of which the individual filaments arecontinuous, which comprises subjecting said fabric to an aqueous bathcontaining a solution of the order of four .to six percent, based on theweight of the solution, of a chemical fiber-curling agent forsuperpolyamides, said agent consisting essentially of a crystallizedphenol, and simultaneously imparting pulse trains of ultra-sonicacoustic wave oscillations to the bath, the frequencies of saidoscillations being within the range of 20,000 to 60,000 cycles persecond, the duration of such treatment in said aqueous bath being notlonger than 15 seconds, and the interval of the interruption betweenconsecutive trains being longer than the period between interruptions,whereby respective individual ones of said continuous filaments becomecurled and spread apart at portions thereof between crossing points ofthe knitted filaments, the effect over the fabric being uniform.

3. In the method according to claim 2, said ultrasonic oscillationsbeing damped.

4. The method of treating a knitted textile fabric comprised ofsuperpolyamide multi-filament yarn of which the individual filaments arecontinuous, which comprises subjecting said fabric to an aqueous bathcontaining a solution of the order of four to six percent of acrystallized phenol, and simultaneously imparting pulse trains ofultra-sonic acoustic wave oscillations to the bath, the frequencies ofsaid oscillations being within the range of 20,000 to 60,000 cycles persecond, the duration of such treatment being not longer than 15 seconds,and the interval of the interruption between consecutive trains beinglonger than the period between interruption, whereby respectiveindividual ones of said filaments become curled and spread apart.

5. The method of treating a knitted textile fabric according to claim 4,said phenol being monohydroxybenzene.

6. The method of treating a knitted textile fabric according to claim 4,said superpolyamide yarn being nylon.

7. The method of treating a knitted textile fabric according to claim 4,said fabric comprising nylon yarn and being in stocking-fabric form.

8. The method of treating a knitted textile fabric according to claim 7,the duration of the individual impulses of said pulse train beingapproximately six cycle periods, and the interval of the interruptionbetween consecutive pulse trains being approximately 0.5 second.

9. A fabric produced by the method of claim 1.

References Cited in the tile of this patent UNITED STATES PATENTS1,679,767 Gminder Aug. 7, 1928 1,989,098 Lillienfeld Jan. 29, 19352,197,896 Miles Apr. 23, 1940 2,484,014 Peterson et a1. Oct. 11, '19492,650,872 Goldwasser Sept. 1, 1953 2,800,682 Dooley July 30, 1957FOREIGN PATENTS 806,030 France Sept. 14, 1936 OTHER REFERENCESAlexander: Manufacturing Chemist, January 1951, pages 5-8 and 12.,

Textile World, January 1950, pp. -92, 192, 195.

1. THE METHOD OF TREATING A KNITTED TEXTILE FABRIC COMPRISED OFSUPERPOLYAMIDE MULTI-FILAMENT YARN OF WHICH THE INDIVIDUAL FILAMENTS ARECONTINUOUS, WHICH COMPRISES SUBJECTING SAID FABRIC TO AN AQUEOUS BATHCONTAINING A SOLUTION OF THE ORDER OF FOUR TO SIX PERCENT, BASED ON THEWEIGHT OF THE SOLUTION, OF A CHEMICAL FIBER-CURLING AGENT FORSUPERPOLYAMIDES, SAID AGENT CONSISTING ESSENTIALLY OF A CRYSTALLIZEDPHENOL, AND SIMULTANEOUSLY IMPARTING PULSE TRAINS OF ULTRA-SONICACOUSTIC WAVE OSCILLATIONS TO THE BATH THE FREQUENCIES OF SAIDOSCILLATIONS BEING WITHIN THE RANGE OF 20,000 TO 60,000 CYCLES PERSECOND, THE DURATION OF SUCH TREATMENT IN SAID AQUEOUS BATH BEING NOTLONGER THAN 15 SECONDS, WHEREBY RESPECTIVE INDIVIDUAL ONES OF SAIDCONTINUOUS FILAMENTS BECOME CURLED AND SPREAD APART AT PORTIONS THEREOFBETWEEN CROSSING POINTS OF THE KNITTED FILAMENTS, THE EFFECT OVER THEFABRIC BEING UNIFORM.